A venue is a physical place where an event will be hosted, this may be a convention centre, a hall or just your house. You can specify detail such as sleeping arangements when the event is created.
Note that organizations do not "own" venues, and other organizers can schedule their events at a venue that they did not create. For this reason, once you create a venue, only an admin can edit it.
The geodetic (WGS84) latitude/longitude of your venue. This can be awkward, but it allows us to put a pin on the map. We cannot use post/zip codes because many countries do not have them!
https://www.latlong.net/ will convert an address to a rough lat/lng.